With the exception of her husband, there are few figures in the Democratic Party who boast the kind of magnetism Obama possesses. Democrats have been publicly complaining about Obama for weeks, but their criticism and the media's spotlight on it hasn't changed her schedule. The election is now only 71 days away.

Her charisma — if she put it to use — could open a gusher of much-needed fundraising cash and produce an infusion of grassroots enthusiasm for Democrats fighting for their political lives.

But, so far, the first lady has been largely absent from the campaign trail. Embattled candidates can hear the clock ticking down to the midterms and are anxiously awaiting signs that she will emerge from the White House soon. They say they need her to put her shoulder to the wheel.

The announcement prompted some Senate Democrats to draw a comparison with Obama and wonder when the latter would, as one put it, “show up” during this campaign cycle.

“What has she done?” one Democrat on Capitol Hill asked. “There’s nothing to point to.”

Another Democrat in a tight race was even more blunt.

“I don’t want to say she’s been M.I.A. but she’s been M.I.A.,” the person said.

The first lady’s defenders can point to the fact that she has appeared at several fundraisers throughout the year for the Democratic Party. She has sometimes used those occasions to take on Republicans over their criticisms of food nutrition standards she has worked to put in place.

During one fundraiser for Democrats last month, Obama asked donors to “dig deep” and help the party in what she called her husband’s “last election.”

“There is something you can do right now, today, to make a difference and that is to write a big fat check,” she said, speaking at a fundraiser in her hometown of Chicago. “I kid you not. I’m going to be honest with you. That’s what we need you to do right now. We need you to write the biggest fattest check that you can possibly write.”

Last month, in a push to rally the base and Democratic donors, Obama kicked off a voter drive for the Democratic Congressional Campaign Committee, asking the audience to be “as passionate and as hungry” as they were in the presidential election cycles in 2008 and 2012.

“In fact, you need to be even more passionate and more hungry to get Democrats elected to Congress because these elections will be even harder and even closer than those presidential elections,” she said in the video.

But Democrats, specifically those in tight races, argue that they’d like to see more action from her. In one sense, that is a tribute — they know how valuable her support could be.

“They’re anxious for her because she’s so popular,” one Democratic official put it, adding that, President Obama aside, there are only three truly top-tier draws in the party: Michelle Obama, Bill Clinton and Hillary Clinton.

Still, the first lady has never fully embraced politics and has been reluctant to hit the campaign trail in years past.

In 2010, West Wing aides had to continuously prod her, making the case that she was badly needed on the campaign trail. After some reluctance, she finally agreed after the White House laid out an in-depth plan outlining how she could be most useful. In 2012, she devoted the bulk of her time to ensuring her husband was reelected.

“By all accounts, she cherishes her private time and wants to spend as much time at home with her family” as possible, said one Democratic strategist. “But when she goes out there, she’s great on the campaign trail and she’s absolutely dynamite.”

DSCC Director Guy Cecil agrees.

“The first lady is not only popular with Democrats, but with independents and Republicans as well,” Cecil said, adding, “She has been incredibly supportive of our campaigns and our work to hold the majority.”

In recent weeks, the first lady has devoted much of her time to her family, including the vacation with her husband and children in Martha’s Vineyard, Mass., that just ended.

Political observers expect her to devote more time to Democratic candidates in the fall. But, even if that happens, the suspicion lingers among some in the party that she could have done more.

“The question isn’t will she or won’t she?” one Democrat said. “It’s how much time she’ll devote and if it’ll be too little, too late.”